All about transaction fees in Electrum

To get a more detailed idea about how much you will be paying in fees go to Tools menu > Preferences > Fees tab and check “Edit Fees Manually”. Now on the send tab you will see additional fields that show the transaction size and the total amount in fees you will pay:

As you can see fees depend on the size of your transaction in bytes and the fee rate in terms of satoshis per byte. There are 100,000,000 (100 million) satoshis in a bitcoin.

Fee estimation

So how long will your transaction really take to confirm? Because of the decentralized nature of the bitcoin network there is no way to tell with certainty. We can only estimate.

The fee slider, shown below the fee field in the screenshot above, is Electrum’s way of suggesting a suitable fee based on market conditions. The further to the left you drag the slider the lower the fee but the longer the transaction takes to confirm and the opposite is true for the right side.

There are three options for fee estimation algorithms that you can choose between via tools > preferences > fees tab > fee estimation:

  • Static is essentially a fixed range of 1-300 satoshis per byte. It does not take market conditions into account.
  • Mempool and ETA suggest suitable fees based on fee market conditions.

If you pause your mouse cursor over the fee slider you will get a tooltip explaining how long the transaction will take to confirm.

In the case of ETA that will be how many blocks. On average we get a block every 10 minutes so that’s how you can estimate how long it’ll take. Note that average is not the same as always. Sometimes we get blocks mere seconds apart and sometimes it can be hours between blocks.

In the case of mempool it’ll be the size in megabytes of unconfirmed transactions that pay more. Since an average block contains 1.3MB of transactions you can estimate how long your transaction will take to confirm by dividing the amount given there by 1.3MB and multiplying by 10 mins.

What determines the size of my transaction?

The number of inputs and outputs determines the size of your transaction. If you regularly received small amounts of money from faucets or mining pools in the past your transaction would be very large because of the large number inputs so you would pay a relatively high fee.

You can click on the preview button on the send tab to see how many inputs and outputs there will be in your transaction.

I’m really cheap. Tell me how I can save even more money?

Check “Use Replace-by-fee” under Tools menu > Preferences > Fees tab so that you can low ball the fee initially and bump it later on if you need to.

If the transaction status on the history tab says “Local” then you know that it has been ejected from the mempool of the electrum server you are connected to and it is time to rebroadcast it. You can do that by right clicking on the transaction, choosing “Details” and then clicking on “Broadcast”.